index.html.erb

<%= debug params %>

<ul>
  <li><%= image_tag Post.find(params[:id_1]).image(:medium) %></li>
  <li><%=  link_to "Vote", vote_path(params[:id_1]) %></li>
</ul>

<ul>
  <li><%= image_tag Post.find(params[:id_2]).image(:medium) %></li>
  <li><%= link_to "Vote", vote_path(params[:id_2]) %></li>
</ul>